Our invention concerns a golf shaft with an outer wood tube and an inner tube bonded therein and made out of metal or other conventional material.
Objectives of our invention include to improve a golf club in respect to the following (which are illustrated respectively in FIGS. 12-16):
(a) To reduce radial torque or twisting of club head and shaft that is aggravated by off-center hits of the ball by the head. This will be called "twisting" herein. PA1 (b) To reduce flexing or bending of the shaft in downswing prior to ball impact. Less flexing will mean less distance for the club head to travel to recover normal club disposition in which the axis of the shaft is a straight line. This will be called "downswing flexing" herein. PA1 (c) To reduce flexing or bending of the shaft past the recovered position. The more the shaft flexes during the upswing past the recovered position the more the shaft flexing adds loft to the club face and the more the head and shaft twist which misaligns the club face to the right thereby deflecting the ball to the right. This will be called "flexing and twisting after recovery" herein. PA1 (d) To reduce flexing of the shaft caused by centrifugal force that makes the toe of the club head hit the ground before the heel. This will be called "club head toeing" herein. PA1 (e) To reduce vibrations as the ball is struck in general and to dampen the harsh vibrations particularly caused by off-center hits, by hardcovered balls, by cold weather conditions, by cast steel heads, and by other deficiencies in club constructions. This will be called "club vibration" herein. PA1 U.S. Pat. No. 2,085,915 PA1 U.S. Pat. No. 3,502,124 PA1 U.S. Pat. No. 4,119,388 PA1 U.S. Pat. No. 772,043 PA1 U.S. Pat. No. 3,738,765 PA1 U.S. Pat. No. 3,368,257 PA1 U.S. Pat. No. 1,513,350 PA1 U.S. Pat. No. 3,854,838
Further objectives include: to improve a golf club in the foregoing respects while maintaining the weight thereof at about the level of clubs with conventional shafts; to provide a club of improved feel; to devise a way to satisfactorily bore the wood part of the shaft; to provide means to alleviate the problem of hairline cracks at the lower end of the wood part of the shaft; to devise means to join the club head to the combined outer wood tube and inner tube made of conventional material; to provide an improved golf club in various aspects of flexing, twisting and vibration while maintaining other desirable characteristics of conventional golf clubs; to devise an attractive club having the appearance of a wood shaft while providing suitable economy of manufacture considering the quality of the product and while providing suitable durability; and to provide a golf club shaft with the appearance and softer feel of wood, especially hickory, and with the reliability and consistency of steel.
A preliminary examination search was conducted and the searcher cited patents identified as follows:
The only patent cited concerning a golf club shaft, which was made of more than one material, is U.S. Pat. No. 2,085,915 but in cross-section that patent specifies packing material between inner and outer annular metal parts. The other search patents concern lathes, boring wood poles, etc., and were not devoted to golf clubs. U.S. Pat. No. 1,513,350 describes drilling wood objects with a rifle bore drilling machine. U.S. Pat Nos. 3,738,765 and 3,502,124 describe drilling of poles and the use of air, rather than liquid, to convey chips during wood drilling. All-wood shafts become largely replaced with metal upon legalization of metal by the USGA about 1925. The wood shafts were unsatisfactory because of various physical properties, i.e., warping, low strength in torque, breakage, etc.
Our invention will be best understood, together with additional advantages and objectives thereof, when read with reference to the drawings.